The present invention generally relates to a packaging system comprising a sealing device for forming a sealing line on a package film enclosing an article and thus packaging the article, and in particular to a packaging system capable to adjust the operation speed thereof for accommodating different assembly lines of the articles to be packaged.
Package films made of plastics or other heat sealable materials are widely used in packaging a variety of products, such as foods, compact disks for computer software and music and books, to protect the products from being damaged or contaminated. In a packaging process, a package film is placed around an article to be packaged. Edges of the package film is then heated to seal together along sides of the article.
A conventional packaging machine forms an L-shaped sealing line along two adjacent sides of an article to be packaged. Movable members carrying heat-sealing blades are allowed to move with respect to each other for engaging and thus forming a sealing line on the package film enclosing an article. The overall efficiency of the conventional packaging machine is thus dependent upon the cycle time that is required for the movable members to engage each other and then separate again. In the conventional packaging machine, the distance between the movable members when they are separated from each other is in general constant. Thus, the cycle time is fixed. When the conventional packaging machine is incorporated in an assembly line for packaging articles manufactured in the assembly line, the assembly line may suffer an undesired reduction of overall efficiency due to inconsistency in operation speed between the packaging machine and the assembly line.
It is desired to provide a packaging machine for overcoming the above mentioned problems.
Accordingly, an object of the present invention is to provide a packaging machine that is capable of adjustment of operation speed and thus operation efficiency.
Another object of the present invention is to provide a packaging machine comprising movable sealing blades distanced from each other, the distance therebetween being adjustable for changing the operation speed of the packaging machine.
To achieve the above objects, in accordance with the present invention, there is provided a packaging machine comprising a machine chassis and a sealing device supported on the machine chassis. The sealing device comprises upper and lower movable members each carrying heat-sealing blades for performing heat-sealing operation of a package film enclosing an article to be packaged. A driving system is arranged in the machine chassis, comprising a power cylinder or a solenoid mechanically coupled to the upper and lower movable members by a linkage for reciprocally driving the upper and lower members between an open position where the members are separated from each other at a predetermined distance and a closed position where the heat-sealing blades engage each other. An adjustment device comprises a screw rod threadingly engaging the machine chassis and a platform attached to an end of the screw rod. The power cylinder is pivotally attached to the platform whereby when the screw rod is rotate to change the position of the power cylinder with respect to the machine chassis, the distance between the movable members is changed in correspondence thereto. Changing the distance between the movable members causes a change of the operation speed of the sealing device.